Changing to an adjustable Ritchey stem on my Trek 7.3. My bars are 25.4 and the stem I'm looking at is stated to be for 25.8-26. With this being half a millimetre bigger, will it still fit ok?

Many thanks!

1 Answer 1


No, it doesn't seem like much, but that stem won't fit your bars without a shim. Very wise of you to ask. Nitto (and probably others) make shims for just this situation. They cost about $10 US. The old standard for road bikes was 25.4 mm (for the most part), but there seems to be a move towards 26.0 mm.

  • 1
    Yes, very good catch on your part. The measurement is close, I think that the stem would probably clamp the bars enough that you might think that they were ok, but not tightly enough to be safe. I'd expect pulling on the bars when climbing or a sudden stop would be enough to make them move. That could be quite dangerous.
    – dlu
    Jul 26, 2015 at 14:42
  • 1
    Drink cans make excellent shims. Soft Al won't scratch Al-bars and because of the softness will help clamping. Don't forget grease on the contact surfaces be it steel shims, Al shims or just the bar in the stem.
    – Carel
    Jul 28, 2015 at 16:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.